Automatic collet chuck



Filed. Sept. 6, 1941 3 Sheets-Sheet 1 INVENTOR. Cue 77s M BELL Ari-maven Aug. 10, 1943. .c. M. BELL 2,326,322

AUTOMATIC COLLET CHUCK Filed Sept. 6, 1941 3 Sheets-Sheet 2 III I 11: s

VENTOR. Cue r/s BELL 4 7" TOENE'K Aug. 10, 1943 c. M. BELL. 2,326,322

AUTOMATIC COLLET cnucx Filed Sept. 6, 1941 :5 Sheets-Sheet :s

' INVENTOR. Cuer/s M. 351.1.

ATTORNEX' Patented Aug. 10, 19.43

UNITED STATES 5 Claims.

The present invention 'relates to lathe chucks, and particularly to "a collet chuck which can be released or engaged without stopping the lathe. It is a considerable advantage in the quantity Production of articles alathe to be able to insert the rough -part and, remove the finished 7 piece without stopping the machine. Particularly is this true where a short, simple operation is tube performed and thetime for stoppingand starting the lathe wouldbe a very great proportion of the total time available for operation.

Various automatic brakes have been developed for, this purpose but are unsatisfactory, due to a multiplicity of parts and consequent increas in first cost and in maintenance. j

. My ,invention permits accurate centering, clamping and release of the Work without inter,- fering in any way with the continuous rotation of. the lathe. This result is accomplished by changing the collet position through planetary gearing renderedoperative by braking mechanism controlled through a brake lever or through manual pressure on abrake drum by attendant. a v An object of my invention is thus, primarily,

to increase the speed and economy of operation of a lathe. Another object is toyprovidaior the rapid and automaticgcenteringof work in,-

serted in arotating chuck. :A further-objectis to provide meansfor clamping and-unclamping work in a lathe chuck while the latter is rotating at a constant speed; Yet another-object-is -to Briefly, my invention comprises interposing a pair of brake drums and aLdifierentialgear train between the head spindle and the coll'et, and

tightening or releasing the collet bylretarding one or the other of the drums whilethe spindle and collet continue to rotate in unison.

The invention has been illustrated .in the drawings, wherein:

Fig. 1 is a perspective viewof the assembled form of my invention.

the lathe Fig/2 is a longitudinal, sectional view of the device of Fig. 1- shown attached to af1athe.;

is a transverse, fragmentary, sectional view of myinventio n, showing the collet-actuating gears in ;the planes indicated by. lines iii-r11 of Fig. 2. 1 r Fig.- l is a fragmentary',.sectional view, illustrating; anv alternative structure 'for attaching chuck to the spindle. g

.lfig, 5 is a schematic, sectional view, illustrating an alternative form of; the control lever mechanism used vith my invention. 1

Fig. (i isa fragmentary, transverse section,

showing an alternative gear'arrangement, taken as indicated'bylines VI'VI of Fig 7.

.Figp'i' is a; transverse, sectional'view ofthe embodiment of Fig. 6,

Fig, 8 is a fragmentaryview of an alternative. brake drum and internal gear'construction.

in l" have; shown a preferred e'mbodi- -ment of the automatic colletchuck of my. invention, detafihe ftfrom the lathe "with which it is.

- to be used and indicated generally 'by the ref- The lathe may be of any not a partof the present invention. .assembly i includes a split collet-Z, mounthead'spindle 5 (shown in Fig; 2) ofalathe.

The collet Eris engaged with, vor released from, stock to lie-machinedthrough; the rotation rela- I. tive to hub of' tightening brake drum 6 or rei fleasing brake device 'l'. Theihead spindle 5 will be assumed,*for purposes of this description, to

be rotating continuously during operation in a counterclockwise direction; as seenin Fig. "1; Relative rotation between head spindle 5' and: "the druz n'fi or l is produced in response to brak; ing actionagainst the drums by gearing vvith in hub i; to be described hereaiterl-Drumsfi} and l are smooth surfaced androunded on the corners s o thatthje'y may be controlledlby pres: sure directly thereagainst of the operators hand, .if desired. t

,iTightenins I lever iii are, rockably mounted on afco'mmon shaft ii, in turnsecured'b-y aiig I! to the lathe j;

ed. 'rne jig l2 may-be made in twopieces, a upper member ll shaped to fit over. the inner ;-tracks l5;and l8 of 'thelathe, and-aibottomplate lt; :through:which a bolt H is disposed to clamp. -the' jig' .elementstogether and fto the lathe. Ji

l2 has been" shown as 'shaped to fit lathe tracks of alternate flap shape-'15 and'inverted-V-shape v i a chuck hub 4 which maybe securedto' brake lever-d and releasing brake wide toothed collar 6 I I prefer to make the pinions and shafts on opposite sides of the device of such mass that there will always be both a static and a dynamic balance to prevent vibra tion. In some cases it maybe necessary to use two complete sets of pinions displaced 90 from Pivots 2i and 22 are preferably aligned vertically r with the. spindle 5. Peripheral grooves 25 and 21 of truncated V- shape are formed about the drums 6 and I to engage the arcuate brake shoes 19 and 20, respec-- tively. The interior gearing arrangement within hub 4 is utilized to translate a braking eifect at the periphery of drum 6 or 1 into clamping or releasing of the work. Hub 4 is made in two parts, a collet-controlling hub portion and I a spindle-engaging hub portion 3|, 'These parts are secured together by symmetrically-spaced bolts 32, passing through radially extended flanges 34 and 35 formed integrally with hub' portions 36 and 3|, respectively.

'* An annular portion-is machined out of the adjacent peripheral edges of each of the flanges'34. and 35 to define seats 35 and 31 for rotating fit reception therebetween of flanges 39 and 40, ex- 7 tending radiallyin'ward from drums 6 and I, respectively. When assembled, flanges- 39 and 40 cooperate with seats 35 and 31 to retain the drums 6 and l in proper relation axially of the'hub 4 while freely permitting rotation relative to hub The adjacent portions of,

"4 or to each other.

flanges 39 and 40 are cut out,-forming annular seats 4| and 42 to receive internal ring gears 44 and 45 flush with the adjacent inner faces 46 and 41 -ofdrums 6 and l. press-fitted into seats 4I'an'd42 and additionally secured, as by bolts 49, to th e drums'ii and 1.

Alternatively, gears 44 and 45 may be formed integrally with drums 6 and 7, as shown in Fig. 8.

Flange 48 is reduced in radial extent below the root'sof teeth I4l, as shown at I42, or even elim- "inat'ed entirely, so that the teeth may be breached out in'one simple operation to produce a'unified gear and drum I44. The gears'44, and

V 45 -'are the first links in the gear train convert- *ingrotation of drums 6 and l relative to hub '4 into gripping or releasing action by the collet 2. The adjacent faces 46 and 4'! of flanges 34 and '35 are bored inalignment at 59 and 5| and at 52 and 54 to act as journals fo the reception of r stub'shafts 55 and 55. A recess 51 is out around "bores and 52 into the inner face 4'! of flange .3 4-to receive meshing pinions 59 and 60, rotating I freely onstub shafts and 56. Outer pinion 59 meshes with-ring gean 44 while inner pinion 6B nular seats 62 and 64' are cut into the inner. peripheries of adjacent flange faces and.- 41" SeatsEZ ami'sa' are proportioned so'that the collar 6 HS freelyrotatable therein but is restrained against axial movement.

' Diametrically opposite'pinions 59 and G0, bores [I'll and 1| are formed inalignment in adjacent flange faces 45 and 41 to act as journals for a cut into inner flange face 4'I,"a pinion 14 'meshing outwardly with ring gear 45 and inwardly with'the: remaining half of, the axial extentv of v Gearsj44 and 45 may be L each other to achieve this aim.

If the brake lever 9 is operated by the lathe attendant, drum 6 will be retarded; and by the engagement ofinternal gear '44, through pinions 59 and '50, with collar 5|, the latter will be driven clockwise relative to hub '4. Conversely, if lever 19 is operated, drum 1 will be retarded and collar Sldriven counterclockwise relative to drum 4.

In'some' cases where only light pressure is re' "'quired to grip the stock, the attendant can operate the-collet by manual pressure against the brake drums and need notuse the brake lever and shoe. I utilize this optional direction of rotation of collar 61 relative to hub 4 to grip or release work by making. my collet 2 in a preferred form and engaging it threadably within collar 6 I.

collet-controlling hub 3B isbored at 15 to receive for about one-thirdjits lengthan inner sleeve iii,- press-fitted therein and further preventedffiom rotating-by astud Ti projecting a plurality (if-symmetrically disposed keyways andstuds, as shown indotted lines. The twothi'rcls of .the length of bore 62 has press-fitted therein an outer sleeve 82, which is flanged out Wardly at 84 beyond the end of hub 36. The outerflanged-portion 84 is tapered inwardly at 85.

'I prefer'to caseharden the'entire outer sleeve member 82 or to form it-of alloy steels of great hardness and toughness. Alternatively, sleeves lfi and 82 might be made in one piece and only theeouter endportion hardened. I

'Inwardly tapering sleeve surface 85 constitutes a seat, against which a'corresponding taper 86,

formed terminally on c'ollet'2, may engage when the collet is traversed axially to the left (see Fig. 2). "The collet body 8l' is slotted at 81 for over half its length. I prefer-to cut'five symmetrically disposed slots, as this -number'appears'to providera more even gripping action. -.0bviously, a greater number of slots could be used, but fewer than three is not desirable; since they then prevent evenness-of action which'is essential to selfcentering of inserted work; Similarly, the use of a pluralityof studs Ti and keyways "l9 and'8ll, spacedbetween adjacent slots 81, equalizes the stresses developed in the collet when engaging and disengaging work;

. Since my collet chuck is designed for mass productionof oneparticular piece, itis not neces- If different sizes of parts be'used'for eachsize of part.

'stub shaft l2,"on Which'is mounted in a recess 13' At the innerend of collet body portion 8! Il form areduced diameter section 89, externally threaded to engagewithin collar Bl. Rotation of collar El relativeto hub 4 will drive collet 2 axially, releasing the work if traversed to the right, or gripping it, if traversed .to the left, to. engage the tapered collet surface 86 with the tapered surface 85 of the sleeve liner 82, I 1

Conventionally, right-hand threads are used actionas to cause the chuck to unscrew from the spindle byits own inertia; Again, it is'o ften d sirable to operate the lathe in the opposite direction to that'assumed 'fQi' purposes of description.

Hence, sometimes I-prefer to modif'y the spindleengaging hub 3i, as illustrated schematically-in 4 1 In Fig. 4, 1 have illustrated a spindle 9 I having a tapered engaging surface 92, onto which fits-a tapered bore 94 formed in spindle-engaging portion 95 of hub 4. An annular locking-groove is out about hub portion 95 torec'eive a radial locking flange 91 formed integrally with a threadedfca'p' 99 Cooper'ating threads I on spindle Jill, lockcap 419 and hub 95 thereto, while 'a'ke'y IUI, set inspindle keyway I82 and hub keyway I04, prevents rotation of the hub 4 relative to the spindle 9 I ,"re'gardless ofth'e direction of the forces acting onthe chuck. 3 "1 In'Fig. 5, I have illustrated an alternativeembodiment of the brake control means, using a single control arm Iifl instead of the two arms 9 and I 9, shown in Fig. 1. Brake shoes'I9 and 2 0 are supported on brake rods III and H2, vertically journaled in a housing member H4 attached to the lathe bed (not shown) by conventional means. Levers I I5 and I56 extend from control arm HG into engagement with rods I II and H2;

-12 I and :22 to 'accommodategears I24 and 425 r, V -m'eshing with ring gears stand 45,'respectively. f Gears 524 and izfi are freely rotatable on stud:

If arm lid is rocked on its pivotal mounting I H to the right, as shown in dotted shafts Iliiand 21, journaled'in aligned bores I29 and IE9 and I3! and-l32 formed in flanges 34 and 35, respectiveiy. Each of gears I24 and I has formed integrally therewith a spur'gear I34 and I35, respectively, having a, toothratio of about 3:1 to eiiecta reduction in speed and consequent] increase in torque transmitted to the collar BI.

, A chuck arranged iorgrippingand releas- I in'g stock during continuous chuck rotation coma flanged 'mounting hub arrangedtobe secu'red'to a powerfsource, a flanged colletmass projection job's is very much-increased by cutting out wasteltimein nstopping and starting his lathe.

e chucked for 'any-"sortioi turningf grinding, buffingor finishingoperation. Iqdairrrr- 1 1 1'. A device for reieasin'g'and grippingistock in a lathe duringcontinuous rotation thereof, compiising-a pair of independently operable-brake drums mounted on the head spindle of said lathe,

differential gearing operable between saiddrurns and a collet actuating, internally threaded ring. a "gear; a-s plit COIlet threadabIy engaged with said ring gear and operable to grip and release stock by axial traversal, brake means selectively operable againstsaid drums comprising a mounting j member arranged to be secured to saidlathe by a single bolt; brake 'r'odsslidably disposed in said mounting memberjbrase'shoes fixed to said rods,

a single control lever, and means for moving said nativiy with said drums,

'rods' by'said lever toengage said shoes alter?" prising receiving hub securedrigidly to said mounting hub, a'b'ore formed in said'collet-receiving hub, a hardened liner secured in said-bore, a flared collet-engaging surfaceiformedat the outer end of 'saidliner, a split collet disposed slidably within said liner, means for preventing rotation or said collet andsaid liner withins'aidbore, a. taperedsurface formed about the outer endf of said 'colletfand arranged to cooperate'withfsaid ilared line'r'sur'fa'ce to -compress andreleases'aid cated axially of said hub, cooperatingfrecesses formed co'aXlal'ly witliilfl said hubs'aninternallyf I threaded-ring gear disposed within said ceoper- T ating recesses; threads formed about the inner end 'of sai'd"collet and "engaging threadably with said ring 'g'e'an' cooperating recesses and bores V r formed 'inthfeadjacentffaces'ofsaidhub flanges;

differential gearing disposed in said recesses and meshing with said ring gear, annular recesses formed peripherally of the adjacent faces of said flanges, a pair of annular brake drums disposed Spur gear I34 meshes with half the wide gear 7 teeth of collar 5| and links it with ring gear 44 Spur gear I meshes with the remaining half width of the teeth on collar iii, linking it with gear construction, as described in connection with Fig. 8. g

In summary, it will be seen that I have provided a device with but few moving parts and of simple construction for the rapid release or gripping of work to be machined. The operator needs I also may wish to use a one-piece brake drum and ring concentrically about said hubsand extendin radially into said annular recesses, internal gears formed on said drums within said annular re-,

' cesses and meshing with said differentialgearing,

andbraking means selectively engaging said drums and actuated by'a single lever.

3. A chuck arrangedfor gripping and releasing stockduring continuous chuck rotation, comprising a flanged mounting hub arranged to 'be secured to a power source, a flanged collet-receiving hub secured rigidly to said mounting hub, a

bore formed in said collet-receiving hub, ahard- Q ened 'linersecured in said bore, a flared colletengaging surface formedat the outer end of said liner, a split collet di sposed slidably ,within said liner, means for preventing rotation of said collet and said liner within said bore, a tapered surface I, formed about the outer end of said collet and arranged to" cooperate with; said flared liner surface to compress and release said split collet portion when said collet is ireciprocated axially'of said hub, cooperating recesses formed coaxially within said hubs, an internally threaded ring gear fho -specialskill to use it, and yet his output n J described fmy device'in conjunc -b'jj tion with a lathe, it will beobvious that it is equal- 1 ly applijcable'toany machine in which parts are l r to-- with the other of said drum disposed within said cooperating recesses; threads formed about the inner end "of said collet and annular chamber cut peripherally into the flanged portion of each of said hubs, apair of annular brake drums disposed about saidflhubs, ;an internal gear on each of said drums extending engaging thread'ably; with. said 'ringigear," an

concentrically into said; annular chamber, two

sets of journals formedwin alignmentin said said-drums, a pinion mounted on the other of said shafts meshing with said first-mentioned pinion and with said internally threaded ring 'ge'ar a third. set of journals formed in said hub flanges and. angularly displaced from the previand a pinion mounted on said shaft meshing I internal gears and with said ring gear. I

4. A chuck arranged for gripping and releasing receiving hub secured rigidly to said mounting hub, a bore formed in said collet-receiving hub,

a hardened liner secured in said'bore, a flared collet-engaging surface formed at the outer end ofsaid liner, a split collet disposed slidably within said liner, means for preventing rotation ofnsaid collet and said liner within said bore,

,a taperedsurface formed about'the outer end;

of said collet and arranged to cooperate with said flared liner surface tocompress andrelease said split collet portion when said collet is reciprocate'd axially of said hub, cooperating recesses iormedcoaxially within said hubs,an internally ,threaded'ring gear disposed within said cooperating recesses, threadsformed about the inner end. of said collet and engaging threadablyrwith I -saidyring gear,; an annular chamber cut periphrl terallyinto, the flanged portion of' each 'of said hubs, a.;- pair-of annular-brake drums disposed about said hubs, an internal gear on each of said drums extending concentrically-into said annular chamber, two sets of journals formed in alignment in said flanges, a shaft disposed in each of mounted relative thereto said sets of journals, a pinion mounted on one Of saidshafts andmeshing with said internal gear on one 'of said drums, a pinion mountedonthe other 7 of saidshafts meshing with said firstmentioned pinion and with said internally threaded ringgear, athird set of-journals formed in said hub flanges and angularly displaced from the previously mentionedsets, a shaft disposed therein, apinionmountedon said shaft meshin with the other ofsaid drum internal gears and withsaid ring --gear, and braking means independently operable against said drums fixedly and actuated by a single 1ever. v 5. A chuck arranged for gripping and releasing stock during continuous chuck rotation, compris- 1; ing a flanged mounting hub arranged to be ously mentioned sets, a shaft disposed therein,

secured -to a power source,; a' flanged colletreceiving hub s'ecured rigidly to said mounting hub, a bore formed in saidcollet-receiving hub, a hardened .liner secured .in said .bore, a flared collet-engaging surface formed at the outer end of. said liner,- a split collet disposed slidably within said liner, means for preventing rotation of saidicollet and said liner within said bore, a tapered surface formed about the outer end of said collet and arranged to cooperate with said flared liner surface to compress and release said splitcollet portion when said collet is reciprocated axially of said hub, cooperating recesses formed coaxially within said hubs, an internally threaded ring gear disposed within said cooperating recesses, threads formed aboutythe inner end of said collet and engaging threadably with said ring gear, an annular chamber out peripherally into the flanged portion of each of said by asingle lever.

drums extendingconcentrically into said annular chamber, cooperatinggear recesses formed in the adjacent faces of said hub flanges, reduction "gears disposed in said recesses meshing with said ring gear and meshing separately with said drum internal gears, and braking means mounted independently of said chuck and arranged for alternative engagement with said drums and actuated CURTIS M. BEL-L. 

